Cannot comment on the rib x, but taught on a ribcraft 4.8 many times, and hated it, very narrow beam and moving around was always difficult, build quality was OK not the best and the way it was rigged was always trouble, there was always something needed fixing.
Just my experience of a well used 4.8

If you're buying new, then this is an expensive package considering it's just under 5m. Ribcraft fit Suzuki DF60 (109kg), but boat is rated for 75hp if you were likely to be hauling heavier loads, or using for diving. Agree with earlier post regards build. It wasn't that long ago that owners of other Ribcrafts noticed the forward anchor hatch didn't even have Sikaflex beading to stop water ingress.

Having said that I've found my boat (2010) to be well made. No hull or tube issues. If you opt for double jockey set-up, then space becomes a premium. Definitely opt for wear patches on tubes. Windscreen is nice, but not practical. Under-deck fuel tank would be nice, but not essential. The portable tanks (25 litres) fit under the jockey console, but only after Ribcraft fleece you for the GRP fitting trays. The double A frame is also expensive. You have been warned.

I use the boat in the North Sea and west coast Hebrides Atlantic. Been out in some fairly rough stuff, and have been impressed with sea-keeping. It doesn't slap and handles well with 2-3 up onboard.

The Rapide 750kg trailer isn't a patch on a Rollercoaster or DeGraff. It's too narrow and the boat sits high.

Without trying to throw a spanner into the works - what about looking at the Ribquest 4.8m?

My experience of the Ribcraft is exactly the opposite of ashbypower's.

Our club has a Ribcraft 4.8 and two Avon SR4s. It's a lot wider than them (and the SR4.7 I had a go in once last year). You wouldn't get two seat pods side by side in it comfortably, but at 4.8m, I don't think I'd expect to.

The boat itself has been trouble-free for (I think) almost 20 years. Apart from one tube section that started losing pressure fairly recently, any problems have been engine-related.

It handles our occasional nasty, 6", short waves with aplomb too.

Whether it's a good family boat, I'm not in a position to say, as ours is a safety boat with a single seat pod.

I not sure I've ever heard of Rib-X. A quick Google search hasn't turned much up.

thanks for the replys, I need the boat for a family of 4 (9 and 7 year old children). in the south of france mainly, the sea always seems to be choppy. water skiing and general touring around. I had a bombard SB500 that was a bone shaker. I am not planning on diving, or intentially going out in big seas. Is a valiant V450 a compromise? If you google rib-x it comes up number 1 result.

thanks for the replys, I need the boat for a family of 4 (9 and 7 year old children). in the south of france mainly, the sea always seems to be choppy. water skiing and general touring around. I had a bombard SB500 that was a bone shaker. I am not planning on diving, or intentially going out in big seas. Is a valiant V450 a compromise? If you google rib-x it comes up number 1 result.

what constrains you to sub 5m?

I have children not dissimilar ages. Not sure I'd want them sitting on tubes in chop for any reasonable distance. People here tend not to like benches but for a family of 4 on a wee boat its a practical solution.